In partnership with MAC, known for their receivers, barrels, and gearboxes, we're releasing a huge batch of CRBN gearboxes for your CRBN Uppers! (CRBN Gen 2 coming Christmas)

This CRBN Gearbox allows you to use a CRBN Upper with ANY V2 airsoft replica engine system! It's now possible to use PolarStar drop-in engines such as the F2, F1, and Jack in your build, as well as Wolverine and Redline engines!

Expand the capability of your CRBN upper builds with an AirTac Customs CRBN Gearbox!

This AirTac Customs CRBN Gearbox includes:

• Machine milled to perfection
• Included centering grub screws for HPA engine
• Gearbox screws for both halves
• Matte black finish
• Allows compatibility of a CRBN Upper with any drop-in HPA engine
• Does not include selector plate or trigger board screw

Compatible with:

• [CRBN] G&G-style V2 Lowers (SSG1, ARP9, SSG556, etc)
• Any other V2 lower, upper, and grip.